scholarly journals DEPENDENCE OF Cr-Cu-O CATALYSTS ACTIVITY IN THE REACTION OF ETHANOL DEHYDROGENATION ON THEIR PHASE COMPOSITION

2021 ◽  
Vol 19 (1) ◽  
pp. 25-31
Author(s):  
S.H. Mammadova ◽  
◽  
A.A. Ahmadova ◽  
Keyword(s):  
Copper Oxide ◽  
Atomic Ratio ◽  
Oxide Catalysts ◽  
Degree Of Crystallinity ◽  
Ethanol Conversion ◽  
Crystallinity Degree ◽  
Conversion Reaction ◽  
X Ray ◽  
Acetic Aldehyde ◽  
The Degree Of Crystallinity

The work deals with the reaction of ethanol conversion over chromium copper binary oxide catalysts. It showed that acetaldehyde is the main product of the ethanol conversion reaction. As the temperature rises, the direction of the ethanol conversion reaction shifts toward dehydration of ethanol into ethylene. Studies revealed that the atomic ratio of chromium to copper in the composition of the catalyst also has a strong effect on the activity of chromium-copper oxide catalysts. It established that samples with high chromium content in the composition of the catalyst display the greatest activity in the reaction of acetic aldehyde formation. So, on the sample Cr-Cu = 6-4, the yield of acetaldehyde reaches 82.5% with a selectivity of 97.6%. X-ray studies found that Cr-Cu-O catalysts consist mainly of initial oxides and in some samples indicate the chemical compound. X-ray studies showed that as the copper content decreases, the degree of crystallinity increases in the studied catalytic system. Comparison of the activity of Cr-Cu-O catalysts with their crystallinity degree revealed that the rise in crystallinity degree of chromium-copper oxide catalysts leads to the increase of acetic aldehyde yield and its selectivity in the ethanol conversion reaction.

The Effect of Compression Force on Alteration of Desloratadine and its Multicomponent Crystal Crystallinities Using X-Ray Diffraction and ATR-FTIR Techniques

2018 ◽  
Vol 787 ◽  
pp. 43-51
Author(s):  
Ahmad Ainurofiq ◽  
Rachmat Mauludin ◽  
Diky Mudhakir ◽  
Arif Budi Setianto ◽  
Sundani Nurono Soewandhi
Keyword(s):  
Crystallite Size ◽  
Degree Of Crystallinity ◽  
Attenuated Total Reflectance ◽  
Compression Force ◽  
X Ray Diffraction ◽  
Crystallinity Degree ◽  
X Ray ◽  
Peak Broadening ◽  
The Degree Of Crystallinity ◽  
Better Than

This work studied the effect of compression force on the desloratadine (DES) and its multi-component crystal (MCC) formulation and focused on the molecular crystal behavior of DES and MCC after compression. Crystallinity behavior of drugs in a mechanical process is to be interesting manner. In this research, DES and MCC were compressed using hydraulic presser equipped with 13 mm flat-face punch under different compression pressures in a range of 25 – 350 MPa. The solid state of DES and its MCC was evaluated using powder X-ray diffraction (XRD) and attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy. Single XRD was carried out to confirm the molecular structure of crystal lattice. Powder XRD diffractogram under different compression forces was compared to the crystallinity degree, crystallite size and peak broadening. Those parameters were processed using Origin software. Crystallinity degree was calculated using Ruland’s methods, meanwhile, the crystallinity size was calculated using Scherrer’s equation after corrected to the broadening (full width at half maximum; FWHM) and diffraction baseline. As increasing the compression force, degree and size of crystallinity and FWHM were altered. In addition, the degree of crystallinity and crystallite size of DES and MCC decreased, while the FWHM increased. Furthermore, alteration of PXRD in DES was higher than that of MCC which had no alteration as increase as the compression force. FTIR result showed that neither DES nor MCC had no significant alteration after compression. However, the tabletability of MCC was better than DES owing to the potential slip plane of MCC.

Effects of the Different Crystallization Time on Synthesis of Zeolite 4A from by-Products of Polysilicon Production Process

2011 ◽  
Vol 347-353 ◽  
pp. 246-251
Author(s):  
Xing Yong Liu ◽  
Min Li ◽  
Hong Chen ◽  
Wei Wei
Keyword(s):  
Production Process ◽  
Degree Of Crystallinity ◽  
Crystallization Time ◽  
Crystallinity Degree ◽  
Structure Morphology ◽  
Zeolite 4A ◽  
Single Structure ◽  
Ft Ir ◽  
The Degree Of Crystallinity ◽  
By Products

Pure form,single phase and high crystalline zeolite 4A samples were synthesized during hydrothermal treatment of by-products in polysilicon production process. The effects of the different crystallization time on the degree of crystallinity, skeleton structure, morphology, size of the particle and its distribution of zeolite 4A samples were investigated using XRD,FT-IR,SEM and Zetasizer. The results indicated that the zeolite 4A sample featured high crystallinity degree, excellent dispersivity, high purity and single structure.

scholarly journals Hemp Fibre Reinforced Poly(Lactic Acid) Composites

2007 ◽  
Vol 29-30 ◽  
pp. 337-340 ◽  
Author(s):  
M.A. Sawpan ◽  
K.L. Pickering ◽  
Alan Fernyhough
Keyword(s):  
Lactic Acid ◽  
Degree Of Crystallinity ◽  
Poly Lactic Acid ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Hemp Fibre ◽  
Reinforcing Material ◽  
Fibre Loading ◽  
The Degree Of Crystallinity

The potential of hemp fibre as a reinforcing material for Poly(lactic acid) (PLA) was investigated. Good interaction between hemp fibre and PLA resulted in increases of 100% for Young’s modulus and 30% for tensile strength of composites containing 30 wt% fibre. Different predictive ‘rule of mixtures’ models (e.g. Parallel, Series and Hirsch) were assessed regarding the dependence of tensile properties on fibre loading. Limited agreement with models was observed. Differential scanning calorimetry (DSC) and x-ray diffraction (XRD) studies showed that hemp fibre increased the degree of crystallinity in PLA composites.

Study of the structure and thermal characteristics of nanocomposites based on polyvinyl alcohol and intercalated montmorillonite

2019 ◽  
pp. 089270571987919
Author(s):  
Volodymyr Krasinskyi ◽  
Ivan Gajdos ◽  
Oleh Suberlyak ◽  
Viktoria Antoniuk ◽  
Tomasz Jachowicz
Keyword(s):  
Thermal Stability ◽  
Differential Scanning Calorimetry ◽  
Acrylic Acid ◽  
Polyvinyl Alcohol ◽  
Thermal Characteristics ◽  
Degree Of Crystallinity ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
The Degree Of Crystallinity

The structure and thermal characteristics of nanocomposites based on polyvinyl alcohol (PVA) and montmorillonite (MMT) intercalated with polyvinylpyrrolidone were investigated by X-ray diffraction analysis and differential scanning calorimetry. The modification of PVA with intercalated MMT reduces the degree of crystallinity of the resulting nanocomposites but significantly increases their thermal stability. Under ultrasound, the intercalated MMT was completely distributed in a PVA solution and formed a monocrystalline structure. Films based on PVA with modified MMT were cross-linked at 110°C in the presence of 5 wt% acrylic acid and 0.5 wt% Ferrous(II) sulfate as an initiator. The formed films have a homogeneous cross-linked structure.

The Degree of Crystallinity in Natural Rubber. IV. The Degree of Crystallization in Frozen Raw Rubber and Stretched Vulcanized Rubber

1950 ◽  
Vol 23 (2) ◽  
pp. 310-319 ◽  
Author(s):  
J. M. Goppel ◽  
J. J. Arlman
Keyword(s):  
Natural Rubber ◽  
Experimental Evidence ◽  
Theoretical Investigation ◽  
Degree Of Crystallinity ◽  
X Ray ◽  
Crystallization Point ◽  
Vulcanized Rubber ◽  
Degree Of Crystallization ◽  
The Degree Of Crystallinity

Abstract An improved x-ray technique has been worked out to determine the degree of crystallinity in natural rubber. Inaccuracies which sometimes occur in quantitative x-ray measurements were eliminated, and it has been shown that the amount of crystalline rubber, both in frozen samples of raw rubber and in stretched vulcanized rubber, could be determined fairly accurately. More experiments were carried out and the results are described. These results, which confirm the current views on the problem of crystallization, point to relatively low degress of crystallization, even in highly stretched rubber, and they agree with some other experimental evidence and with a recent theoretical investigation.

scholarly journals Determination of the Degree of Crystallinity of Poly(2-methyl-2-oxazoline)

Polymers ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 4356
Author(s):  
Evgeniy M. Chistyakov ◽  
Sergey N. Filatov ◽  
Elena A. Sulyanova ◽  
Vladimir V. Volkov
Keyword(s):  
Thermal Destruction ◽  
Polymer Melt ◽  
Boron Trifluoride Etherate ◽  
Degree Of Crystallinity ◽  
X Ray Diffraction ◽  
X Ray ◽  
X Ray Scattering ◽  
Cationic Ring Opening Polymerization ◽  
The Degree Of Crystallinity

A new method for purification of 2-methyl-2-oxazoline using citric acid was developed and living cationic ring-opening polymerization of 2-methyl-2-oxazoline was carried out. Polymerization was conducted in acetonitrile using benzyl chloride—boron trifluoride etherate initiating system. According to DSC data, the temperature range of melting of the crystalline phase of the resulting polymer was 95–180 °C. According to small-angle X-ray scattering and wide-angle X-ray diffraction data, the degree of crystallinity of the polymer was 12%. Upon cooling of the polymer melt, the polymer became amorphous. Using thermogravimetric analysis, it was found that the thermal destruction of poly(2-methyl-2-oxazoline) started above 209 °C.

scholarly journals Microwave-Assisted Preparation of Zinc-Doped β-Tricalcium Phosphate for Orthopedic Applications

2020 ◽  
Author(s):  
Ali Taha Saleh ◽  
Dheyaa Alameri
Keyword(s):  
Tricalcium Phosphate ◽  
Degree Of Crystallinity ◽  
X Ray Diffraction ◽  
X Ray ◽  
Microwave Assisted ◽  
Ftir Spectrometer ◽  
Diffraction Peaks ◽  
Orthopedic Applications ◽  
The Degree Of Crystallinity ◽  
Good Agreement

A novel two-step methodology delivering zinc into the structure of β-tricalcium phosphate (β-TCP) has been investigated. Incorporating wet precipitation of calcium-deficient apatite [Ca9-xZnx(HPO4)(PO4)5(OH)] (x = 0.00–1.00 mol) using a microwave-assisted process followed by two-hour calcination at 1000 °C has been conducted to generate a ratio of 1.48 of Zn doped β-TCP. The products were characterized by X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectrometer, and field emission scanning electron microscope (FESEM). Our results confirmed that the product was crystalline Zn2+-doped β-tricalcium phosphate. The incorporation of Zn+2 into the β-TCP lattice resulted in a shifting of diffraction peaks to higher 2θ values, which were attributed to the substitution of larger-sized Ca+2 ions with smaller-sized Zn2+ ions. A reduction in the intensity of the XRD peaks was also observed due to the reduction in the degree of crystallinity of the samples. Lattice parameters along the a and c-axis showed a gradual decrease in length with an increase in the amount of Zn2+ doping. This decrease was attributed to the replacement of Ca+2 ion by the smaller-sized Zn2+ ions. The microstructure of the powders consisted of microscale aggregates fused together. EDX analysis of all samples showed that the Zn2+ doping had successfully taken place and the amount of Zn2+ present in the samples was in good agreement with the theoretical values.

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